1. Field of the Invention
The present invention relates to treadmills and more particularly, to a driving mechanism for treadmill, which has the motor and the related transmission parts set inside a tubular driving roller for rotating the tubular driving roller in moving an endless running belt.
2. Description of the Related Art
A conventional treadmill, as shown in FIG. 1, comprises a pair of rollers 11 mounted on a frame (not shown), an endless running belt 10 wound around the rollers 11 under a selected tension, a roller pulley 12 mounted on the shaft 110 of one roller 11 for receiving a drive belt 15, and a drive mechanism comprising a motor 13 having a drive pulley 14. The drive belt 15 is wound around the roller pulley 12 and the drive pulley 14 at a drive tension created by the selected tension in the running belt 10. This design of treadmill has drawbacks as follows:
1. Because the roller pulley 12, the motor 13, the drive pulley 14 and the drive belt 15 are disposed outside the endless running belt 10, they require much installation space.
2. The drive belt 15 may lose its tension after a long use, resulting in a driving error. In this case, the tension of the drive belt 15 must be corrected.